iommu/mediatek: Add a flag DCM_DISABLE

In the infra iommu, we should disable DCM. add a new flag for this.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20220503071427.2285-12-yong.wu@mediatek.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>